With Spring Training fast approaching, MLB.com will take a look at a different aspect of this year's Nationals squad each day this week. Today's topic: What's the difference?

WASHINGTON -- It was only the first day of February, 16 days ahead of when position players were scheduled to report to Spring Training, and the biggest acquisition of the Nationals' offseason had already arrived in West Palm Beach, Fla.

Washington returns much of the same roster that won 95 games and the National League East last season, but its biggest change was the addition of outfielder Adam Eaton. The Nats traded away a prized collection of prospects to acquire the center fielder, and the deal initially raised some questions about whether he was worth it. However, the Nationals are betting Eaton will be the difference-maker in their quest to go from a playoff team to World Series champions.

Even if his accomplishments have flown a bit under the radar, Eaton has been one of the best outfielders in baseball during the past three seasons. His average slash line over that span is .290/.362/.422 and has been worth 5.1 Wins Above Replacement, according to Baseball Reference. He has been an elite defender during past seasons, even if there is some uncertainty about his ability in center field. But Eaton's overall consistency during the past three campaigns is part of the reason the Nats were interested acquiring him.

Eaton will take over in center field and hit near the top of the order, which will help lengthen the Nationals' lineup. His on-base skills should also provide plenty of run-scoring opportunities ahead of Bryce Harper and Daniel Murphy. Although he might not fit seem to fit the traditional model of a player who can transform a lineup, the Nationals believe Eaton can.

"He plays with an edge," general manager Mike Rizzo said after the trade. "He's playing 100 miles an hour with his hair on fire, he hustles, he will dive for balls, he will steal a base, he goes into second base hard."

The addition of Eaton also triggered a few more changes, with Trea Turner shifting back to shortstop and Danny Espinosa being dealt to the Angels. The only other change to the lineup will be at catcher, where Derek Norris takes over after Wilson Ramos left via free agency to join the Rays. The Nats also still do not have a clear closer, after free agent Mark Melancon signed with the Giants.

Otherwise, six of the team's eight position players and all five starting pitchers return from last season -- meaning the Nats will primarily rely on the same group in their quest to repeat as division champions.

Eaton, the most notable addition, with his early arrival has signaled he is ready to make an impact.

Washington's pitchers and catchers have their first workout on Feb. 16. The full squad will have its first workout on Feb. 19. The Nats open their spring slate on Feb. 25 against the Mets in Port St. Lucie.

Jamal Collier covers the Nationals for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.